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Chunking: using what you already know to turn many small pieces into a few bigger ones, for strings and for lists.
Paper packet. Every task here also exists on screen, where it is checked automatically; answers written on paper are not assessed by Nydus. When you are back at a device, enter your answers there.
You will group a string or a list into chunks you already know, count the raw pieces and the chunks, and check that each chunk unpacks.
The desk from lesson 1 holds about four pieces, and a piece fades when nothing keeps it fresh. A load count lists the pieces a task asks you to hold.
This lesson changes one word in that sentence: piece. A piece does not have to be one digit or one word. If you already know a group as a single thing, the whole group is one piece. That is a chunk.
| Term | What it means |
|---|---|
| Chunk | A group of items you already know as one thing, so it costs one piece. |
| Chunking | Regrouping a long string or list into chunks, so fewer pieces are held. |
| Raw count | The number of separate items before any grouping: ten digits is a raw count of ten. |
| Chunk count | The number of pieces after grouping. |
| Known unit | Something already in long-term memory: a year, an acronym, a word, a familiar number. |
Chunking does not make the desk bigger. It makes each card carry more.
Try this: F B I C I A U S A. Nine letters is a raw count of nine, more than the desk holds. Now read it as FBI, CIA, USA. It is the same nine letters, but it is three pieces, because you already know each group.
The work is done by your long-term memory. You can only chunk what you already know. 1776 is one piece for someone who knows the Declaration of Independence, and four digits for someone who does not. So chunking is not a talent. It is knowledge put to use.
Grouping by rhythm alone — saying 4-9-2, 7-1-8 in threes — helps a little even when the groups mean nothing, because it makes the string easier to say over. Grouping by meaning helps much more, because a meaningful chunk is held as one thing.
Another way: steps
Another way: picture
Picture nine loose beads on a table, then the same nine beads on three strings of three. You can pick up three strings in one hand. You cannot pick up nine loose beads.
In 1973 William Chase and Herbert Simon showed chess players a board from a real game for five seconds, then asked them to set it up again from memory. A master placed far more pieces correctly than a beginner did.
Then they used boards with the pieces scattered at random, in positions no real game would produce. The master's advantage almost disappeared.
The master's desk was not larger. The master had seen thousands of games and knew common groups of pieces, such as a castled king with its pawns, as single patterns. Random boards had no such patterns, so everyone was back to one piece at a time. That is the whole of chunking in one experiment.
Strings — codes, numbers, passwords — are grouped by finding known units inside them. NYC1492USA is ten characters and three chunks: a city, a year, a country.
Lists — groceries, errands, names — are grouped by category or by where they belong. Nine groceries become three meals, or three aisles. Then you hold the three groups, and each group reminds you of its members.
In both cases, check each chunk honestly. A group only counts as one piece if you really do know it. A made-up group you will not recognize later is still several pieces.
Say each chunk aloud as you tap a finger. Then, without looking, try to unpack each chunk back into its items. If every chunk unpacks cleanly, your count is right. If one chunk comes back fuzzy, it was really two or three pieces, and the count should go up.
Many US numbers are printed in groups on purpose. A phone number is split 3-3-4: area code, exchange, line. A Social Security number is split 3-2-4. A credit card number is usually printed as four groups of four. The groups do not add meaning on their own, but they give a rhythm, and the parts you already know — your area code, the first digits of your own card — become single pieces.
Grouping helps you notice mistakes too. When you read a card number back in groups of four, a missing digit shows up as a short group.
Say you need tortillas, black beans, salsa, eggs, bread, milk, pasta, garlic and tomatoes. That is nine items, a raw count of nine. Group them by the meal they are for: taco night (tortillas, beans, salsa), breakfast (eggs, bread, milk) and pasta night (pasta, garlic, tomatoes). Now you hold three meals, and each meal calls up its three items, because you know what goes into it. A list on paper is still safer for a big shop; the meal groups are what help when the list is left at home.
Chunking is a trick anyone can use on anything. It only works on material you already know something about. A random string with no known units stays near its raw count, whatever rhythm you give it.
More grouping is always better. Groups that are too large stop being single pieces. A made-up nine-letter group is not one chunk.
Good chunkers have better memories. They have more knowledge in that area. A chess master's advantage vanished on random boards.
Count the raw pieces.
Code: NYC1492USA → 10 characters
Every letter and digit is one piece before grouping.
Look for units you already know.
NYC (a city) · 1492 (a year) · USA (a country)
Each of these is already in long-term memory.
Group the string into those units.
NYC | 1492 | USA
The grouping follows the known units, not a fixed length.
Count the chunks.
3 chunks
Ten characters became three pieces.
Check that each chunk unpacks.
NYC → N, Y, C · 1492 → 1, 4, 9, 2 · USA → U, S, A
Every chunk comes back whole, so the count of three is honest.
Count the raw items.
rice, chicken, broccoli, oats, bananas, yogurt, bread, ham, cheese → 9 items
Nine separate items is well over four.
Look for groups you already know.
stir-fry dinner · breakfast · sandwiches
You already know what goes into each meal.
Sort each item into its group.
stir-fry: rice, chicken, broccoli · breakfast: oats, bananas, yogurt · sandwiches: bread, ham, cheese
Each item belongs to exactly one meal.
Count the groups.
3 groups of 3
You hold three meals; each meal recalls its items.
Check by unpacking each group.
stir-fry → 3 items · breakfast → 3 · sandwiches → 3 · total 9
All nine come back, so nothing was lost in the grouping.
Count the raw pieces.
212-555-0199 → 10 digits
Each digit is one piece before grouping.
Look for known units.
212 is your own area code; 555 is a familiar exchange.
Known groups cost one piece each.
Count the chunks.
Why does *IRS* count as one piece for most US adults, but *QZX* counts as three?
A chunking plan for the Wi-Fi password *ZOO2024LAX* is half done. Fill in the later rows.
| Plan | |
|---|---|
| Raw count | 10 |
| Known units | a word, a year, an airport code |
| Grouping | |
| Chunk count |
Match each string to the grouping that turns it into known chunks.
| NASA | 1969 | NFL | CNN | USA | 1776 | FBI | NAS | A19 | 69 | |
|---|---|---|---|---|
| NASA1969 | ||||
| NFLCNN | ||||
| USA1776FBI |
A locker label reads *CIA2001NBA*. Fill in the raw count and the chunk count for someone who knows all three groups.
Raw count: a. Chunk count: b.
Optional chunked recall practice. Nine words appear for twenty seconds. They fall into three categories. Group them as you read, then write back as many as you can, in any order. This is practice, not a test of your memory, and you can skip it.
Ask someone to read you the list, then cover it and write what you remember:
You are packing for a weekend camping trip with no list to hand. Group the six items by the job they are for.
| Item | Group |
|---|---|
| tent | |
| stakes | |
| stove | |
| fuel | |
| flashlight | |
| batteries |
Lesson test: one question per skill, one attempt each, no hints. Your answers are checked when you submit.
For each string, write the raw count and the chunk count for someone who knows every group in it.
| String | Raw count | Chunk count |
|---|---|---|
| 19452001 | ||
| ABCNBCCBS | ||
| 911USA |
Pick a number or a list you need this week. Count its raw pieces, group it into known units, and count again. Next: taking pieces off the desk entirely. A trial in this course is practice. What is kept is what you wrote on this device today; it is not a score, it is not a test of your memory, and it is never compared with anyone. If you notice trouble with memory or thinking that is new or changing, tell your own doctor or clinician; this course is general practice, not an assessment or treatment. Stopping takes nothing more than closing the page: your place is already saved, and the lesson opens where you left it.
13. Your turn: a phone number with a known area code, step 3
212 | 555 | 01 | 99 → 4 chunks
Two known groups plus the last four digits said as two pairs.